Conventionally, such a motor-driving apparatus of a washing and drying machine has a plurality of inverter circuits that drives a plurality of motors so that a rotation drum, a compressor and a blow fan are driven by each pair of an inverter circuit and a motor. For example, such a washing and drying machine is disclosed in Japanese Patent Unexamined Publication No. 2005-198933.
However, a conventional motor-driving apparatus of a washing and drying machine has following problems. Adopting an inverter circuit that drives a motor with rectangular waves of 120° makes loud vibration noise. Similarly, adopting an inverter circuit that drives a motor with sinusoidal waves, due to differences in revolution speed of each motor, carrier frequencies and processors (although a description on the in-detail configuration is not given), the sinusoidal-wave control is interfered by power switching noise. As a result, the aforementioned configuration has difficulty in obtaining a stable driving in a practical use.